In general, there is a need to develop heating and/or cooling systems that are more environmentally friendly and that are less reliant on fossil fuels. Some existing systems have used alternative energy forms, such as solar and geothermal energy, to provide heating and/or cooling in a building. In some existing systems, a combined group of systems (e.g., solar and geothermal) may each take a turn at heating when appropriate heat is available. Such combined systems where solar and geothermal systems are operating independently, however, may not maximize efficiency.